Today many domestic swimming pools have automatic cleaners which operate through the suction provided by the pool filtration pump. Water entraining debris and other dirt is sucked from the submerged surfaces of the pool through the cleaner to a filtration unit and returned, clean, to the pool.
The cleaners referred to operate best at a certain flow rate and to maintain this flow rate a relief valve is usually included in the cleaner apparatus and has a marked effect on the operation of the cleaner.
One problem with known type of relief valves used for the purpose above set out further is that they are often either blocked or held too widely open by debris entrapped therein. A second problem which often occurs is that on starting of the filtration equipment the pump induces a flow which is insufficient to cause the machine to work but does induce flow through the relief valve.
It is the object of the present invention to provide a simple relief valve which will at least mitigate the above disadvantages.